A research group from Nagoya University and Tohoku University has discovered
new compounds that can control stomatal movements in plants. The research
team found compounds that show stomata closing activity, which is expected
to be useful for drought tolerance to suppress withering of plants, and also
stomatal opening activity, which would lead to increased carbon dioxide
uptake by plants.

Regulation of stomatal openings is essential for plant growth as well as
survival in response to various environmental conditions. Stomata consist of
a pair of guard cells and open in response to the blue light present in
sunlight. Opening of stomata leads to carbon dioxide uptake, explaining why
photosynthesis occurs during the day. When plants are under dark conditions
(night) and/or drought stress, the plant hormone abscisic acid (ABA) is
biosynthesized and induces stomata closure to prevent water loss from the
plant.

Using the herb Benghal dayflower as a model plant, the research team
screened over 20,000 compounds. They managed to find hit compounds after a
year of random screening. They found 9 compounds that suppress light-induced
stomatal opening by more than 50%, and 2 compounds that induce stomatal
opening even in the dark.

"This was the best moment in our research, to find that the molecules that
we had discovered had an effect on suppressing the withering of leaves,"
says study leader Professor Toshinori Kinoshita. "The fact these compounds
induce stomatal closure by a different mechanism to the plant hormone, ABA
is important."

[www.itbm.nagoya-u.ac.jp]